Elevated intraocular pressure (IOP) is the major risk factor associated with the etiology of glaucoma, a progressive optic neuropathy that can ultimately cause blindness. Prostamide analogs represent potent therapeutic agents in clinical management of glaucoma and other conditions associated with elevated intraocular pressure. The synthetic prostamide analog used to reduce IOP includes (9S,11R,15S)-9,11,15-trihydroxy-17-phenyl-18,19,20-trinor-5Z,13E-prostadienoic acid ethylamide
known under international nonproprietary name bimatoprost, currently marketed by Allergan as Lumigan™—0.03% bimatoprost ophthalmic solution for the treatment of open-angle glaucoma and ocular hypertension (Drugs Aging, 2002, 19, 231).
US2005/209337 discloses crystalline physical form of bimatoprost, which we designate as form A. The form is characterized by powder x-ray diffractometry, IR DRIFTS (KBr) spectroscopy, DSC and TGA. The present invention includes new polymorphic form of bimatoprost which is the most thermodynamically stable polymorph of bimatoprost and method for preparation thereof.